Files Connect for on-premises external data sources is available
for an extra cost in the same editions.

Make Files More Visible with Topics
Topics aren't just for opportunities, events, orders, feed posts, and all those other objects anymore! Now you can add them to your files, too. Adding topics to files is available via API, and in Salesforce Classic. Searching for topics and viewing the feed items they’re associated with is available in Salesforce Classic and Salesforce1.

Toggle Between "Viewer" and "Set by Record" File Access
Files attached to records now have a new way to set access via Sharing Settings. Instead of being limited to Viewer access only, you can set access to Set by Record. This feature is available in Salesforce Classic only.

Delete Files Included in Content Packs
File owners can now delete a file without having to first remove it from a content pack, which saves time and streamlines file management. Deleting a file from Salesforce removes all versions of that file from all content packs, including content packs the user doesn’t have access to, like those in Private Libraries. This feature is available in Salesforce Classic only.

Connect to Box from Salesforce (Generally Available)
Let your users access, share, and search Box content right from Salesforce. Salesforce users can share Box files with other Salesforce users, Chatter groups, and records. Files Connect enforces the Box file-sharing rules, so users can choose to share a file only with specific people, with all people in the same Box domain, or to people outside the company. This feature is available in both Lightning Experience and Salesforce Classic.

Control Whether a Files Connect External Object Is Searchable
Now you can decide whether to let users find an external object’s records via SOSL and Salesforce global searches. Validate and sync an external data source to automatically create external objects, then select the new Allow Search option for each external object your users need to search. This feature is available in both Lightning Experience and Salesforce Classic.